m42racer

As I was involved indirectly with the MLS Gasket through my association (engines biult by) with Performance Developments I must add my little bit here. As they are the company which first did this Gasket and supply Guru and others, I asked about the MLS Gasket and its merits.

To answer someone here, many engines use this type of Gasket and many have open deck design. If the MLS Gasket failed because of the Block design, the standard design wide or narrow fire ring would do the same. The MLS design is just a more modern design. The sealing surface or fire ring is only around the Cylinder, same for closed decks. The reason for closing the deck is to help with upper Cylinder distortion when the Head is torqued. I was present when my new Block was tested. They installed the Head and torqued it, then measured the Cylinders for concentricity etc. The results were scary. To run higher boost, and or make more power with Cylinders like this would be crazy. That is the reason why Performance Developements are closing the deck. I am going to start a new post telling the story of my new engine, the new parts that will be offered and hopefully have pics showing some of them.

If you have other problems and the Gasket becomes a sort of fuse, the fact the the Gasket failed is purely luck. As many times the Gasket fails, you could also experience other problems. If your A/F ratio is off, and you have any detenation, other wrongs happen also. Your Gasket may fail, I'm told you should check the heat treat on your stock Pistons too. Ring wear, Cylinder distortion and much more I was told that I cannot remember, can happen.

In the end, most people, me included are wary of trying something different if we do not know to much about it. We will stay with something we know is inferior, instead of trying something new.

I suggest, if you have any questions regarding the use of this type of Gasket, call Performance Developments.

pk951

I will add my two cent's worth. This was through a second party they put one of these metal gasket from Huntley- Racing, and coolant was leaking in to the cylinder's. So then they installed a WF gasket no problems since. I am not saying this is the norm. But the verdict is still out on these metal gasket, when people have used them for more than a few thousand miles, say fifty thousand miles. Then we can say that it's one hell of a gasket.

Dan87951

I thought the gasket was a saftey precaution to prevent further more expensive damage. If your head gasket keeps blowing then just don't fix the head gasket, find out why it keeps blowing. I just blew one not to long ago and replaced it with a stock gasket because I would rather have the gasket go before my pistons do. Does this seem logical? Danno I called you and left a message yesterday on your chips you and I have been discussing, cause I think the reason my HG went was because of the improper A/F ratio.

m42racer

pk951,

Everyone is entilted to an opinion. The opinion of some of the best engine builders out there, is that these are the best. BTW, they are well proven in other engines. We 944 owners just need to open our eyes and discover that our technology is way behind.

Head gaskets are lost typically because of other resaons. The use of the MLS should be because of their better construction. They do not offer any miracle cure for some other problem.

Jon Schepps

Hope this thread is still active, 'cause its very timely for me (head off, deciding which gasket to put in).

First, there seems to be some confusion between the composition of the Cometic vs. Huntley vs. Guru offerings. If I understood correctly, the Cometic MLS and Huntley are identical - namely, the 3-layer metal gasket with viton coatiing. The Guru is a 3-layer metal gasket with no viton coating (also made by Cometic), and requires a spray-on gasket sealer. Correct?

Secondly, having exmined my failed WFR gasket, I discovered that it is constructed as a full metal (with tiny perforations) core, with fiber-coated top/bottom. This metal core extends under the fire-rings, therefore, at the rings there are 3 layers of metal - top and bottom rings, plus core.

I'll post pictures shortly, but the obvious physical damage is the burnt fiber section between a coolant passage to the head and the #4 fire ring. Yet, the ring itself does not appear to be burned. I examined all the rings under magnification and none appear to have burnt through the inside edge.

Another physical feature is a puckering of the fiber section adjacent to the fire rings of several cylinders. I'll try to capture this in the photos.

The head of #1 cylinder shows what looks like some blow-by, yet the corresponding fire ring surfaces look OK. Its not yet clear to me where the failure occurred.

Jon

Sean Hall

I talked to Cometic. The guy I talked to said Cometic isn't doing anything different with the gasket made available from Guru/Performance Developments or any of the other tuners.

I can't find any info on the Guru/Perf. Developments gaskets to make them any different, so take it for what its worth.

Maybe Guru and/or Perf. Developments will take this opportunity to explain how their gaskets are "different".

Sean

TonyG

Jon Schepps

Here's what happens:

You have detonation which will deform the fire ring. This deformation will cause the gasket to be pushed outward. The only place for the gasket to go is to flex and extend into the coolant passage.

If you measure your fire rings, you'll see that they are not round.

The reason the gasket material is off, is because of the combustion gases passing through it on their way to the cooling system, which pressurizes up the cooling system, and pushes coolant out.

Although there is a perforated metal core, it's not rigid enough to prevent the deformation of the fire ring. Once the fire ring gets deformed, it's a matter of a short period of time before the cooling system starts getting pressurized.

Jon Schepps

Here are photos of the gasket, head and block surfaces. Due to file size limitations, I'll send them in separate posts.

Here's the gasket. Note the fiber is burnt away on #4. The rings are intact on all cylinders. If anything #1 shows some possible leakage at 5:00, but its not obvious if this is the failure.

Jon Schepps

Here's the cylinder head. Photos look worse than real thing due to lighting / contrast. Some darkening adjacent to where the burnt part of the gasket gasket.

TonyG

Also, #2 shows some potential problems at 6:00 and 11:00 as if the ring has been pushed out... or it may be just the photo angle...

Did you measure your fire rings? Are they perfectly round?

The piston tops are pretty black too... They look wet/sooty.

Is there an oil control problem? How much oil are you going through?

Jon Schepps

Here's the head mating surface. Again, #1 and #4 suspect.

Jon Schepps

Here's the puckers in the gasket.
I measured the diameters of each ring:
#1: 101.9 mm min and max
#2: 101.8 min, 102 max
#3: 101.9 min, 102 max
#4: 102 min, 102.9 max

New gasket is 102 mm.

Diagnosis?

Jon.

TonyG

Detonation.

I've got quite a few wide fire head gaskets that look exactly like yours.. sitting on the shelf.

Jon Schepps

Pistons are pretty black, but not too bad. The wetness is just from some oil I sprayed on walls. Piston tops and plugs were dry prior to tear-down.

BTW, the failure was not catastrophic. I began loosing small amounts of coolant out the overflow on the track (on boost).
Car is set at 17psi max.

Jon.

mutzman951

Jon Schepps,
your HG doesn't look as bad aa mine did, but I was running more boost and had a real bad lean situation which i induced. I installed the gasket from Danno @ Guru and have had no problem. i ran it up to 20 psi yesterday w/o problem. My HG was much more distorted than yours at the #4 cyl 7 O'clock position. I highly recommend the Guru gasket, and if you need, I can help you with it. My parents live near Flemington, and i'm in the USAF reserve @ McGuire AFB, and should be there next week. i'd be glad to help you if you needed. Unfortunately, i've gotten pretty good at doing HG's. i think i've done my HG for the last time this time. i drive my car really hard and i think now it will finally stand the test of time. you can email me @: mutzman951@aol.com if you want any more info. i have digital pics and plenty of experience.

Good luck!

dug